Set prefer language by parsing HTTP_ACCEPT_LANGUAGE header in Silex

kotoblog_set-default-locale-in-silex-by-parsing-http-accept-language-header.php

<?php
$app->register(new Silex\Provider\TranslationServiceProvider(), [
    'locale_fallbacks' => ['en', 'uk', 'ru'],
]);

$app->before(function() use ($app) {
    $locales = $app['translator']->getFallbackLocales();
    $prefLocales = array_reduce(explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']), function ($res, $el) { list($l, $q) = array_merge(explode(';q=', $el), [1]); $res[$l] = (float) $q; return $res; }, []);
    asort($prefLocales);

    $locale = array_reduce(array_keys($prefLocales), function ($default, $prefLocale) use ($locales) { return in_array($prefLocale, $locales) ? $prefLocale : $default; }, $app['translator']->getLocale());

    $app['translator']->setLocale($locale);
});

$app->get('/', function (\Symfony\Component\HttpFoundation\Request $request) use ($app) {
    return $app->redirect('/'.$app['translator']->getLocale());
});

$app->get('/{_locale}', function () use ($app) {
    return $app['twig']->render('index.html.twig');
});

I'm not sure if this comment is the right place to report an issue, but I had to change $res[$l] to $res[trim($l)] in line 8 to make it work properly.